arm64: defconfig: Enable configs for DisplayPort on J721e

Enable DRM and PHY configs required for supporting
DisplayPort on J721e

Signed-off-by: Rahul T R <r-ravikumar@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://lore.kernel.org/r/20220426152926.20953-1-r-ravikumar@ti.com